scholarly journals Styrene-Based Elastomer Composites with Functionalized Graphene Oxide and Silica Nanofiber Fillers: Mechanical and Thermal Conductivity Properties

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1682
Author(s):  
Jaehyeung Park ◽  
Jaswinder Sharma ◽  
Kyle W. Monaghan ◽  
Harry M. Meyer ◽  
David A. Cullen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Graphene Oxide ◽  
Styrene Butadiene Rubber ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
X Ray ◽  
Liquid Mixing ◽  
Silica Nanofibers ◽  
Styrene Butadiene

The mechanical and thermal conductivity properties of two composite elastomers were studied. Styrene–butadiene rubber (SBR) filled with functionalized graphene oxide (GO) and silica nanofibers, and styrene–butadiene–styrene (SBS) block copolymers filled with graphene oxide. For the SBR composites, GO fillers with two different surface functionalities were synthesized (cysteamine and dodecylamine) and dispersed in the SBR using mechanical and liquid mixing techniques. The hydrophilic cysteamine-based GO fillers were dispersed in the SBR by mechanical mixing, whereas the hydrophobic dodecylamine-based GO fillers were dispersed in the SBR by liquid mixing. Silica nanofibers (SnFs) were fabricated by electrospinning a sol–gel precursor solution. The surface chemistry of the functionalized fillers was studied in detail. The properties of the composites and the synergistic improvements between the GO and SnFs are presented. For the SBS composites, GO fillers were dispersed in the SBS elastomer at several weight percent loadings using liquid mixing. Characterization of the filler material and the composite elastomers was performed using x-ray photoelectron spectroscopy, x-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis, dynamic mechanical analysis, tensile testing, nanoindentation, thermal conductivity and abrasion testing.

scholarly journals Preparation and Corrosion Resistance of ETEO Modified Graphene Oxide/Epoxy Resin Coating

Coatings ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 46 ◽  
Author(s):  
Chunling Zhang ◽  
Xueyan Dai ◽  
Yingnan Wang ◽  
Guoen Sun ◽  
Peihong Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
Graphene Oxide ◽  
Epoxy Resin ◽  
Composite Coating ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
X Ray ◽  
Resin Coating ◽  
Epoxy Resin Coating

Improving the corrosion resistance of epoxy resin coatings has become the focus of current research. This study focuses on synthesizing a functionalized silane coupling agent (2-(3,4-epoxycyclohexyl)ethyl triethoxysilane) to modify the surface of graphene oxide to address nanomaterial agglomeration and enhance the coating resistance of the epoxy resin coating to corrosion by filling the coating with functionalized graphene oxide. Functionalized graphene oxide and coatings filled with functionalized graphene oxide were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The corrosion performance of each coating was studied by electrochemical impedance spectroscopy and a salt spray test. Results showed that the incorporation of functionalized graphene oxide enhances the corrosion protection performance of the epoxy composite coating, and the composite coating exhibited the best anticorrosion performance when the amount of functionalized graphene oxide was 0.7 wt %.

scholarly journals Obtaining and properties of functionalized graphene oxide.

2020 ◽  
Vol 11 (3-2020) ◽  
pp. 84-87
Author(s):  
Y. V. Ioni ◽  
◽  
S. P. Gubin ◽  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Ir Spectroscopy ◽  
Elemental Analysis ◽  
Metal Clusters ◽  
Physicochemical Analysis ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
X Ray ◽  
Organic Functional Groups

The study is devoted to the possibility of surface modifying of graphene oxide with organic functional groups and/or metal nanoparticles. The presence of many oxygen-containing groups makes it possible to conduct surface methylation as well as allows them to be the centers of crystallization for metal clusters and nanoparticles. The obtained substances are characterized by different physicochemical analysis methods such as elemental analysis, x-ray diffractive analysis, IR spectroscopy and electron microscopy.

Fabrication and Characterization of Poly(vinyl Alcohol)/Functionalized Graphene Oxide Nanofibers Produced by Electrospinning Method

2013 ◽  
Vol 747 ◽  
pp. 405-408
Author(s):  
Yuan Hsiang Yu ◽  
Chih Jie Jan
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Functionalized Graphene ◽  
Sem Images ◽  
Functionalized Graphene Oxide ◽  
X Ray ◽  
Electrospinning Method

A series of poly (vinyl alcohol) (PVA)/functionalized graphene oxide (FGO) nanofibers with low feeding ratios of FGO to PVA were fabricated by electrospinning method. In this study, the prepared PVA/FGO nanocomposites were dispersed in water phase followed by electrospinning treatment under different operational parameters (i.e., applied voltage, feeding rate and FGO contents) to give nanofibers of various diameters and morphologies. The morphology, diameter and structure of electrospun nanofibers and FGO were investigated by Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), (TGA) and differential scanning calorimetry (DSC). SEM images showed that the morphologies of the nanofibers were improved by the incorporation of FGO at a low loading content (e.g., 0.1~0.5 wt %) as compared to pure electrospun PVA. The crystallinity and thermal stability of PVA/FGO nanofibers were also studied.

scholarly journals Functionalized Graphene Oxide Shields Tooth Dentin from Decalcification

2019 ◽  
Vol 99 (2) ◽  
pp. 182-188 ◽  
Author(s):  
M.Z.I. Nizami ◽  
Y. Nishina ◽  
T. Yamamoto ◽  
Y. Shinoda-Ito ◽  
S. Takashiba
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Dental Caries ◽  
Epithelial Cells ◽  
Photoelectron Spectroscopy ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
Silver Diamine Fluoride ◽  
X Ray ◽  
Aged Society

This in vitro study assessed the efficacy of functionalized graphene oxide (f-GO) nanocomposites on the decalcification of dentin, because dental caries of the root surface is becoming one of the new problems in aged society. Hydroxyapatite plates (HAP) and dentin slices were coated with f-GO nanocomposites by comparing them to silver diamine fluoride as a positive control, then treated with decalcification solutions such as ethylenediaminetetraacetic acid and citrate at 37°C for 24 h. Scanning electron microscopy (SEM) revealed significant protection of the surface morphology of HAP and dentin. On the other hand, a cariogenic Streptococcus mutans growth was inhibited by f-GO nanocomposites. In addition, cytotoxicity of them to epithelial cells was much less than that of povidone-iodine, which is commonly used for oral disinfectant. We synthesized 5 different f-GO nanocomposites such as GO–silver (Ag), GO-Ag–calcium fluoride (CaF2), GO-CaF2, GO-zinc, and GO–tricalcium phosphate (Ca3(PO4)2). They were standardized by evaluating under SEM, transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry analysis (TGA), and Raman spectra after being synthesized in an aseptic technique. The abilities of GO-Ag, GO-Ag-CaF2, and GO-CaF2 nanocomposites were most preventive for decalcification. In addition, GO-Ag and GO-Ag-CaF2 almost completely inhibited S. mutans growth. However, they did not exhibit cytotoxicity to epithelial cells except at the highest concentration (0.1 w/v%) of GO-Ag and GO-Ag-CaF2. Furthermore, these f-GO nanocomposites exhibited less or no discoloration of dentin, although commonly used silver diamine fluoride causes discoloration of dentin to black. Thus, these f-GO nanocomposites are useful to protect dental caries on the tooth root that becomes a social problem in aged society.

Preparation and Characterization of 3-Glycidoxypropyltrimethoxysilane Functionalized Graphene Oxide

2019 ◽  
Vol 814 ◽  
pp. 112-117
Author(s):  
Kun Yan Wang
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Hydroxyl Group ◽  
Functionalized Graphene ◽  
X Ray Diffraction ◽  
Functionalized Graphene Oxide ◽  
X Ray ◽  
Transmission Electron ◽  
Low Degree

The graphene oxide (GO) was prepared by the Hummers method, and then functionalized by 3-glycidoxypropyltrimethoxysilane. Functionalized graphene oxide (FGO) was characterized by using Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), and thermogravimetric analysis (TG). The results show that 3-glycidoxypropyltrimethoxysilane reacted with hydroxyl group of graphene oxide. The FGO have a sheet-like structure with wrinkles. The shifts of XRD peaks to low degree for FGO indicate the occurrence of intercalation of 3-glycidoxypropyltrimethoxysilane and as well as increase in the thermal stability.

Supramolecular structure of polypropylene fibers formed with addition of functionalized graphene oxide

2020 ◽  
Vol 90 (19-20) ◽  
pp. 2322-2335 ◽  
Author(s):  
Jan Broda ◽  
Marcin Baczek ◽  
Janusz Fabia ◽  
Ryszard Fryczkowski
Keyword(s):  
Graphene Oxide ◽  
Polypropylene Fibers ◽  
Pimelic Acid ◽  
Functionalized Graphene ◽  
Fiber Structure ◽  
Scanning Calorimetry ◽  
Functionalized Graphene Oxide ◽  
X Ray ◽  
X Ray Scattering ◽  
Spun Fibers

Pimelic acid and calcium hydroxide were used to attach calcium pimelate to the surface of graphene oxide. The additive was mixed with isotactic polypropylene granulate. Neat polypropylene and polypropylene with functionalized graphene oxide was extruded into fibers under laboratory conditions. The gravity spun fibers containing different concentration of the additive and the fibers taken at various velocities were obtained. Morphology and elemental composition of functionalized graphene oxide were studied by means of scanning electron microscopy and energy dispersive X-ray spectroscopy. The structure of fibers was examined by means of differential scanning calorimetry and wide-angle X-ray scattering. The ability of calcium pimelate supported on the surface of the graphene oxide to nucleate the β-form of polypropylene was revealed. A considerable amount of the β-form crystals was obtained in the gravity spun fibers. In the fibers taken at moderate and higher velocities the β-form disappeared. The structure of the fibers extruded with the additive was similar to the structure of the fibers extruded from neat polypropylene. At moderate velocities, the content of mesophase in the structure was high. At higher velocities, the crystalline structure built only from α-form crystals was obtained. The paper presents a discussion of the changes observed in the fiber structure in connection with polypropylene nucleation.

Enhancement of styrene-butadiene rubber composites using kaolin covered with metal oxide pigments

2015 ◽  
Vol 44 (2) ◽  
pp. 57-73 ◽  
Author(s):  
Salwa H El-Sabbagh ◽  
Nivin M. Ahmed
Keyword(s):  
Electron Microscopy ◽  
Thermal Properties ◽  
Metal Oxide ◽  
Styrene Butadiene Rubber ◽  
Core Shell ◽  
Butadiene Rubber ◽  
Rubber Composites ◽  
Content Type ◽  
X Ray ◽  
Styrene Butadiene

Purpose – This paper aims to express in detail the rheological, morphological and thermal properties of unpigmented and pigmented styrene-butadiene rubber composites with new prepared inorganic pigment based on kaolin covered with a thin layer of calcium and magnesium oxides or mixed oxide of both together. These new pigments combine the properties of both their constituents (kaolin and metal oxides), which are a new trend in inorganic pigments called core-shell pigments. The pigments used for comparison are kaolin (K), CaO/kaolin (CaO/K), MgO/kaolin (MgO/K) and CaO.MgO/kaolin (CaO.MgO/K). Design/methodology/approach – The different pigments were characterized using different analytical and spectrophotometric techniques, such as X-ray diffraction, scanning electron microscopy/energy dispersive X-ray and transmission electron microscopy, while rubber vulcanizates' rheological, morphological, swelling and thermal properties were examined using different standard and instrumental testing and methods. Findings – The study revealed that there is a significant effect of the new prepared pigments on SBR properties, where the optimum pigment loading was 40 phr for CaO/kaolin, while it was 2.5 phr for MgO/kaolin. Studying the effect of different ratios of oxides on kaolin (5, 10 and 20 per cent), different loadings of these pigments ranging between 2.5 and 40 phr were done for each pigment. These modified kaolin or core-shell metal oxide/kaolin pigments imparted new and improved reinforcing properties to SBR vulcanizates. Research limitations/implications – No research limitations were found. Practical implications – Core-shell MgO/kaolin pigments are eco-friendly and can replace other expensive pigments that are usually used as fillers in the rubber industry with less expenses and comparable efficiency. Originality/value – These new pigments are cheap and efficient and can be used in different fields other than rubber.

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